The full name of pyrroloquinoline quinine lithium salt is trilithium derivative of pyrroloquinoline quinine. Its formula is C14H3N2O8Li3, and molecular weight is 348. It has the following chemical structural:

A substance with the same chemical composition may crystallize with two or more different spatial lattice arrangements. This phenomenon is called polymorphism. The polymorphic behavior of drugs can be of crucial importance in pharmacy and pharmacology, which takes tremendous impacts on drug quality. Varied crystalline forms may differ from each other with respect to one or more physical properties, such as crystal shape, melting point, hardness, solubility and dissociation, state stability and compaction behavior. The differences in physical properties exhibited by polymorphs affect pharmaceutical parameters such as storage stability, bioavailability and efficacy. Therefore, new drug R&D should give more attention to the research on drug polymorphism and crystalline control.
PQQ is discovered as water-soluble B-vitamin by Japanese scientists at 2003. Mice deprived of PQQ grew poorly, have friable skin, develop abnormalities as osteolathyrism, have impaired immune function, are failed to reproduce and are prone to arthritis. Therefore, PQQ is identified as an essential nutrient in vivo. It is thought that PQQ has the same effect on human. Current techniques publish that the molecular weight of PQQ is 330. It is early discovered in microorganism, and it also exists in higher eukaryotes. Its crystalline structure and chemical synthesis are already clarified.
PQQ is a cofactor of multiply essential enzymes. PQQ may ameliorate the function of mitochondrial respiratory chain and the levels of free radicals in vivo. Studies indicate that PQQ deficient mice grow poorly, are failed to reproduce and are prone to arthritis. Therefore, PQQ is identified as an essential vitamin and nutrient in vivo. Studies demonstrate that PQQ has the following functions related with nervous system: (1) Antioxidant: strongly scavenging reactive oxygen species; (2) Alteration of the function of respiratory chain: maintaining the energy metabolism of mitochondria; (3) Activation of signal pathway: stimulating the release of nerve growth factor, recovering and promoting the growth of nerve; (4) Regulating the growth of somatic cells and effectively preventing liver impairment; (5) Attenuating the deposition of α-synuclein protein and preventing the fibrosis of nerve cells. Therefore, PQQ exhibits beneficial effect on treating neurodegenerative diseases, such as Parkinson's disease and Alzheimer's disease (AD).
Pyrroloquinoline quinine lithium salt has been proved to suppress the glycogen synthase kinase-3 activities (GSK-3) and has potential value for treating several mental diseases. Therefore, we pay more attention to the adverse application values of pyrroloquinoline quinine lithium salt. We try to find out its multifactorial mechanisms and apply it on preventing mental illness